Bolt-anchor.



H. w. PLE'ISLEIL BOLT ANCHDR.

APPLICATION FILED 1AN.20| i917.

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UNlTElD STATES PATENT @FFlfUlFt HENRY W. PLEISTER, 0F VESTFIELD, NEW J ERSEY. ASSIGNOR T0 HENRY IB. NEW'HALL.

BOLT-ANCHOR.

Specification of Letters Patent.

Patented Nov. 2?, 1191*?.

@riginal application tiled September 20, 1916, Serial No. 121,104. Divided and this application led January 20, 1917. Serial No. 143,424.

To aZZ whom it may concern:

Be it known that I, HENRY W. Fnnrs'rnn, a citizen of the United States, residing at Westfield, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Bolt-Anchors, of which the following is a specification, taken in connection with the accompanying drawings. This application is a division of my copending application Ser. No. 121,104, Sept. 20, 1916.

My invention relates to bolt anchors.

More particularly my present invention relates to that class of bolt anchors known as anchors lead anchors and screw anchors in which the material of the anchor is formed of more or less ductile material such as an alloy of lead, in which a wood screw will cut its own cooperating female threads. Such anchors are used to hold lighter work than lag shields are used for.

ln the present form of anchors the maximum expansion is approximately at the extreme inner end of the anchor. ln practice this is often a serious detriment in that the wood. screw having forced the anchor out to its maximum expansion binds and it is impossible to bring the head of the wood screw up flush with the work. rlhis requires the hole to be enlarged entailing additional labor and expense, or a different size anchor has to be used.

By my invention l overcome this serious objection and give a longer surface of maximum contact or grip on the exterior of the anchor, thereby giving an increased frictional hold, and distributing this maximum grip over a larger area than with the present form of anchors. My invention further permits the wood screw to cooperate with the anchor with less edort than with the present forms.

My invention further relates to certain details of construction which will be described in the specification and pointed out in the claims.

l have shown in the accompanying drawings different illustrative embodiments of my invention, but of course it is to be understood that my invention is not to be confined simply to the forms illustrated, except as required by the scope of the accompanying claims. In these drawings the same reference numerals refer to similar parts.

Figure 1 is a vertical section of an anchor or screw anchor which is formed of material suiiiciently ductile to permit the wood screw to cut its own cooperating female screwthreads in the anchor;

Fig. 2 is a vertical section of the anchor shown in Fig. 1 expanded in the support, the wood screw cooperating with the ductile anchor is shown in side elevation;

Fig. 3 is a side elevation, partly broken away, of my ductile anchor provided with weakening portions;

Fig. 4 is a vertical section of the ductile anchor in Fig. 3 expanded and cooperating with a wood screw, the support and work to be supported shown in section.

In the illustrative embodiments of my invention, 1 is an anchor having a collar 2, and tines 8. 3. This anchor is provided with an open throat 4, an axial bore 21 having an inclined portion 5 which reaches its nearest approach to the axis at the point 6 and there merges into a cylindrical bore 7 which terminates at the end 8 of the anchor.

In the form of anchors now on the market the bore has an inclined substantially uniform taper extending from near one end to the other end of the anchor. In cooperating with a wood screw, such as 9, the maximum expansion, in the old form, would be approximately at the very ends l0, 10 of the tines 3. 3. ln my invention, by changing the shape of the axial bore and having the inclined surface 5 reach its nearest approach to the axis at a point removed from the end of the anchor, as for example at the points 6, 6, the maximum grip instead of being confined to the inner end of the anchor is distributed along the surface of the anchor from points 11, 11 to 10, 10, which distance of course may be varied. This gives a long surface of contact and increased frictional hold and distributes the maximum grip over a large area, as shown for example in Fig. 2.

In this ligure the wood screw 9 holds the work 12 to the face 13 of the support l-l by passing through the open throat 4, without any expansive cooperation with the collar 2 of the bolt anchor, and then cutting its own cooperating female screw threads in the inclined surfaces 5, 5 and also in the cylindrical surface 7 as shown in this Fig. 2. Not only is it easier to position the wood screw 9 and to obtain a. stronger and more lasting Athin slab of marble or plaster or any other material, the maximum expansion or grip being distributed over a larger area prevents any damage of the support 14. I preferably, though not necessarily, place one or more transverse ribs 17 on the exterior of my anchor, and also preferably longitudinally extending ribs 19, 19 on the collar 2 of the anchor.

As pointed out in my parent case above referred to, the same size anchor and wood screw will hold work of different thicknesses to the support and permit the head 18 of the wood screw 9 to be brought up flush with the work, whatever the thickness of this work may be within a wide range, without the screw jamming in the anchor in a position where its head 18 could not be brought up snugly against the work. This is due to the fact that the point of maximum expansion is extended over a relatively large vportion of the surface of the anchor so that the end of the screw can be brought anywhere along the cylindrical surface 7 of the axial bore, or past the end of the anchor as may be found necessary, to bring the head 18 flush against the work and at the same time obtain the requisite maximum expansion of the anchor. ln the old form, where Vthe maximum expansion is at the end of the ductile anchor, the screw would often am at this point before'its head was brought flush with the work 12, whatever its thickness may be, requiring the removal of the screw anchor and the enlargement of the hole, or the use of a different size anchor.

l may in some cases, to assist the ready insertion of the wood screw, form my anchor with one or more weakening portions 20, 20, Fig. 3, which will permit a portion of the anchor to yieldior spring slightly with relation to the other part. This weakening portion E20 is preferably located adjacent to the termination (i, G of the inclined portion 5 of the axial bore 21. These weakening porv tions 20, 20 are preferably formed by locating comparatively deep valleys 22, E22 preferably on the exterior adjacent to the points 5, G.

he operation of the anchor shown in 3 and i is the same as that shown in Figs. 1 and 2 except that in the former figures as the wood screw 9 passes down the axial bore 21, it springs or moves the ends 23, 23 with relation to the other portion of the anchor 9A: and in this manner opening or tending to open the valleys 22, 22 as shown in F ig. 4E.

lt will be seen that when the expanding means cooperates with the axial bore, said bore is distorted into a. substantially true walls continue with a substantially uniform thickness to the other end of the anchor.

One portion of the axial boreisin the form of a frustum of a cone-whose base is near the entrance of the anchor, its other end merging into substantially a true cylinder at a point locatedbetween the two ends of the anchor. Y Y

Having thus described this invention in connection with several illustrative embodiments thereof, to the details of which 'l do not desire to be limited, what is claimed as new and what is desired to secure by Letters Patent is set forth in the. appended claims.

l. An article of manufacture comprising a ductile anchor having an internal. cavity whose greatest diameter is near its outer end, the diameter of said cavity reducing uniformly until a minimum is reached between the ends and then merging into a substantially cylindrical cavity coaxialwith the anchor.

2. A cylindrical ductile screw anchor having a bore concentric with its longitudinal axis running fromV one extremity to the other, said bore having its greatest diameter at the outer end and tapering inwardly in the form of a frustum of a cone, to a point between extremities, at `which point it merges into a cylindrical bore for the remainder of its length and provided with a weakenino' )ortion substantiall at the oint e Y P of intersection between the tapered and cylindrical portions of the bore.

3. An article of manufacturecomprising a ductile anchor formed substantially of a hollow cylinder, walls of said cylinder being thinnest near the out-er extremity and increasing uniformly in thickness to a point located between extremities where the maximum thickness of the wall is reached from which point tothe other extremity thewall remains of substantially uniform thickness.

4. An article of manufacture comprising a ductile anchor formed substantially of a hollow cylinder, walls of said cylinder being thinnest near the outer extremity, andincreasing uniformly in thickness to a point located between extremities'where the maximum thickness of wall is reached, from which point to the other extremity the wall remains of substantially uniform thickness, and provided with a weakening portionloetween extremities adjacent to the point where the maximum thickness of wall is located.

5. In a bolt anchor the combination of a dnctile anchor having a cylindrical interior bore concentric with the longitudinal axis, the entrance of sai-d bore being in the form of a rustuni of a cone and merging at a point between extremities into a cylindrical bore, and a screw to expand said anchor and to cut its own coperating female threads in the anchor.

6. An article of manufacture comprising a dnctile screw anchor provided with a coaxial cavity of variable diameters provided at its entrance with a longitudinal bore merging into an inwardly tapering bore for part of its distance, said inwardly taper-v ing bore uniformly reducing in diameter as it progresses to a point between extremities, from which point to the farther extremity the diameter remains substantially constant and in the form of a cylinder.

7. In a bolt anchor the combination of a ductile anchor having an axial bore7 which bore near the inner end is cylindrical and concentric with the longitudinal axis, said axial bore having a portion between the ends of the anchor in the form oi a frustuin of a cone which merges at a point between the extremities of the anchor into the cylindrical bore7 and a screw to expand said anchor and to cut its own cooperating feinale tlireadsin the anchor.

HENRY W. PLESTER. Witnesses M. R. RYAN, A. M. WILLIAMS.

@epics of this patent may be obtained for ive cents each, by addressing the Gommissioncr of ateiita, Washington, D. 

